memory with different chip configurations

Ibm / 8187e1u
January 12, 2010 at 09:28:10
Specs: Microsoft Windows XP Professional, 2.793 GHz / 2014 MB
I have two modules of Kingston KVR40064C25/512 installed in my machine at home. These modules have chips on both sides. I found this same memory online but the chips are only on one side. Will the two new memory modules run in dual channel mode with the old. The timings and quantity and speed are the same on all four modules

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January 12, 2010 at 09:32:21
The difference is the chip density used on the modules. Check the motherboard manufacturer's memory support list or possibly the board's manual.

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January 12, 2010 at 09:36:11
CPU-Z only says that this is an IBM board in the Model form field. No model number for the board. The .pdf documentation that came with the computer says only 2700 or 3200 memory is compatible. No real specs on the memory

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January 12, 2010 at 09:52:16
What is the model of your motherboard?

Are you sure you didn't post the module number of the newer RAM? That number should only have chips on one side.

Below is a link to the same RAM as you posted if in fact that is what you currently have.

Kingston part numbers tell the story. KVR (Kingston Value Ram) 400 (speed) 64 (chip size in MB.) 25 (CAS rating) 512 (module capacity.

So 8 64MB chips = 512MB.

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Related Solutions

January 12, 2010 at 10:16:42
I use CPU-Z and it says only IBM for the Model # .

I will have to go home and check the memory inside the machine again tonight

Thank You for your info and any others willing to post on this thread

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January 12, 2010 at 10:33:01
Not on the case somewhere? Download SIW and see what it says. Get SIW at the link below.

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January 12, 2010 at 16:47:12
If the computer you are installing these in as you state:
"Product: Ibm / 8187e1u"
your full model is IBM ThinkCentre M50 8187elu
P4, 2.8ghz.
You've got 4 ram slots, max 1gb per slot.

Brand name computers often have oddball brand name specific ram module ID strings. Ram with a generic (general pupose) ID string may be compatible and work fine, but it's often hard to determine that, because whether it is compatible isn't listed anywhere.

Kingston lists only brand name specific ram module ID strings for your IBM model.

E.g. KTM-M50/512
Kingston doesn't have the info, but vendors selling the same module model show chips on one side, only:

If the KVR40064C25/512 16 chip modules work fine in dual channel mode, the KVR40064C25/512 8 chip modules SHOULD work fine too, since your model supports the KTM-M50/512 8 chip modules.
However, KTM-M50/512 modules will work FOR SURE.

I have noted that some Kingston model modules originally specified to have 16 chips (8 chips on each side) now have 8 chips (on one side).
KVR40064C25/512 is specified to have 16 chips

I don't know whether the 8 chip ones have been wired up so the computer sees them the same as if they had 16 chips or not - if so, the modules will work installed in older computers that require 16 chips that can'r recognize the module if they have 8; if not, the 8 chip ones can't work in older computers.


However, if you search for ram using the mboard model number that's in a brand name system, usually the modules listed have a generic (general purpose) ID string, for any particular brand
(KVR400X64C25/512 is a Kingston generic ID string).

I have determined by searching using: IBM ThinkCentre M50 motherboard
that you probably have an Intel brand name mboard. Chipset: Intel 865G

Open up the computer case and find the mboard model number on the mboard itself.
It's either printed on the mboard surface, or it's on a label that's stuck on top of it - it may be on the printer port if you have one.
It's probably got an Intel brand mboard, model D865G or D865Gxxxx where xxxx is one or more additional letters.

KVR400X64C25/512 modules are NOT listed for ANY Intel mboard:

KVR400X64C3A/512 modules ARE listed for Intel D865Gxxxx mboards:

Therefore, your KVR400X64C25/512 modules are probably running at a CAS of 3, NOT 2.5, on your computer.

KVR400X64C3A/512 modules are also specified as having 16 chips

In order for dual channel support to work, the ram must be installed in specific slots and the two modules in each pair must be identical; however the two sets of pairs do not have to be identical to each other.

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January 12, 2010 at 19:36:25
Thank You Tubesandwires for your time and all great information.

Here is the end result using CPU-Z.

Originally I had 2 x 512 of PC2700 8 chip and 16 chip in slots 1 and 3 IBM and Kingston respectively. With 2 x 512 KVR400X64C25/512 (16 chip) in 2 and 4. Everything in single channel.

Then I used the different speeds separately.

The PC2700 worked @ 2.5 3 3 7 in single mode and the KVR400X64C25/512's (16 chip) worked @ 2 3 3 7 in dual mode only @ 166.2 MHZ (??)

Any reason why the PC3200 runs @ PC2700?

The new KVR400X64C25/512's (8 chip) don't work at all. Not even one 512 by itself.

The only reason I bought the KVR400X64C25/512 is because the price was like $18 a piece and I thought they were 16 chip

The motherboard only says IBM with no model and the chipset is intel i865P/PE/G/i848P according to CPU-Z

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January 13, 2010 at 15:08:00
"Originally I had 2 x 512 of PC2700 8 chip and 16 chip in slots 1 and 3 IBM and Kingston respectively. With 2 x 512 KVR400X64C25/512 (16 chip) in 2 and 4. Everything in single channel."

Dual channel mode is mostly hype. In the real world, all else being equal, most people can't perceive the difference between the two modes - it's at most a very small percentage.

All the installed modules have to support dual channel mode in order for any of them to run in dual channel mode.
I'm assuming you installed the modules in the proper spots to support dual channel mode.
The modules that were in slots 1 and 3 probably cannot support dual channel mode because they are not identical - even if other specs were the same, they have different numbers of chips, and probably different memory densities on the individual chips.
If they - 1 and 3 - weren't running in dual channel mode, then all 4 modules cannot run in dual channel mode, even if the other two - 2 and 4 - do when installed by themselves. If you had removed the modules in slots 1 and 3 and left the other two in, if those two are in the proper slots to support it, they should run in dual channel mode in that situation.

On the other hand, as I pointed out above, Kingston does NOT list ANY Intel brand mboard, which is probably what you have, as supporting using KVR400X64C25/512, but they DO list KVR400X64C3A/512 as being supported.
The KVR400X64C25/512 16 chip modules probably need to be forced to use a CAS of 3 rather than 2.5 on your mboard, at 400mhz.

"The new KVR400X64C25/512's (8 chip) don't work at all. Not even one 512 by itself."

You hadn't mentioned that you already had them.

OK, then, there's some about them that's incompatible with your main chipset, but it probably isn't specifically just the number of chips, it's something else.
Obviously, SOME 512mb modules with 8 chips work - your PC2700 IBM module does.
The Kingston KTM-M50/512 modules should work for sure, since they are specified for your IBM model, despite them probably having 8 chips, according to what pictures of them I found (see above).
Since the KVR400X64C3A/512 modules were originally specified to have 16 chips too, they may not work either, if you can't find any that have 16 chips.

KVR400X64C25/512's (16 chip) worked @ 2 3 3 7 in dual mode only @ 166.2 MHZ (??)

Any reason why the PC3200 runs @ PC2700?

It appears you must set the CAS to 3 or more on this mboard for ram to run at 400mhz.

- It says here:
"Systems with 800MHz FSB processors should use the KTM-M50/xxx (DDR400) part numbers.
Systems with 400 or 533MHz FSB processors should use the KTM8854/xxx (DDR333) part numbers."

If you have a 400 or 533MHz FSB processor, the fsb runs at 333mhz, and maybe the ram can't run faster than that, in that situation,
OR, you may need to set the 400mhz ram speed manually in the bios Setup, because the bios defaults to setting it to 333mhz, which is sometimes the case.

For some chipsets if you populate all the ram slots, all the ram runs at 333mhz max despite the fact fewer modules will all run at 400mhz max (I have an Asus A7V600 mboard that has that situation).

NOTE that all the ram you have installed must support 400mhz in order for any of it to run at 400mhz - if you mix 333mhzand 400mhz modules, all of it will run at 333mhz.
NOTE that it appears the mboard chipset supports ram with a CAS of 3 (or a higher number) at 400mhz, NOT 2.5. If the bios settings allow you to set that lower than 3, the module is forced to run at 333mhz

"The only reason I bought the KVR400X64C25/512 is because the price was like $18 a piece and I thought they were 16 chip"

Ram of a particular size and speed with fewer chips is usually much cheaper than the same with more chips.
Rarely, some sites that sell ram specify the number of chips on the modules.

If you want to find ram with 16 chips, which may not be necessary, try searching using something such as "16 chips" DDR 400 512

However, the module you get has should be listed somewhere as being compatible - e.g. KVR400X64C3A/512 is.

I used "16 chips" KVR400X64C3A/512 and found some "hits", e.g.

Kingston ValueRam 512MB DDR-400 Unbuffered 184-pin DIMM (Picture is for illustration purposes only)
Price: $49.99
Part No: KVR400X64C3A/512
(California; also have web sites in Aus and NZ)
Other sizes with 16 chips:

Or you could get other brand name ram other than Kingston ram that is listed for your IBM or Intel mboard model.
E.g. Crucial.

Or you could get generic ram that is guaranteed to work in your model.
E.g. MemoryGiant, but they don't list 400mhz modules.

"The motherboard only says IBM with no model and the chipset is intel i865P/PE/G/i848P according to CPU-Z"

Like most brand name system builders, IBM doesn't make the mboards in it's desktop systems, but it may have IBM specified markings on the mboard. Usually, mboards in IBM desktop systems were made by Intel. Info I found says your model has the Intel 865G chipset. In theory there should be a D865G or D865Gxxxx model number where x are 1or more extra letters, either printed on the mboard somewhere, or on a stuck on label on the mboard. If you don't see that, there should be an IBM part number for the mboard, probably on a stuck on label that also has a bar code on it - that may be useful to look up which mboard it has.

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January 13, 2010 at 15:24:40
Did you try to run the new sticks by themselves?

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January 14, 2010 at 14:58:33
othehill - yes, I tried the modules alone and single

tubesandwires - The memory went back to Newegg. I will research better next time for sure following your examples. Although now I KNOW the memory I need. Thanks to you.

I found some 1 GB sticks at work that work fine at home.

1 x 3 slots are running the 512's (16 chips) and 2 x 4 are running 1 GB PQI modlues. All dual channel and no real difference in speed as you posted

I really appreciate the time and scope of your responses

One more thing - CPU-Z says latency of mem in slots 1 x 3 is 2. Funny huh?

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January 14, 2010 at 18:49:28
"CPU-Z says latency of mem in slots 1 x 3 is 2"

Each module has a very tiny chip on one top corner on one side that contains the SPD information - that's the info the mboard's bios uses when you set settings in the bios Setup for the ram to "by SPD" or similar, or often it's set to that by default. The manufacturer is supposed to enter the proper info (codes) into that info - brand name ram usually has all, or nearly all, the info possible entered - generic ram may have only the minimum needed entered. CPU-Z may be reading that static unchanging SPD info, as well as providing actual readings otherwise.
In any case, the mboard's bios always auto sets all, or nearly all, the specs for the ram to the least specs of what the modules are rated for when there is more than one module installed, or to less if the user has set settings to specify less.

Your problem is very common, and was compounded by the fact Kingston changed the number of chips from that orginally specified for KVR400X64C25/512. In a very small number of cases, when a manufacturer halves the number of chips, the computer still sees the original requirements for the module memory organization as if it has twice as many chips, because the memory on the chips is still organized as expected, or the way the chips are wired up makes them seen that way to the main chipset.
Add to that the fact that it appears your 865 whatever chipset was never specified to support using KVR400X64C25/xxx but mboards with that chiposet series are specified to support using KVR400X64C3A/xxx or the KTMxxxx modules, as above.

Ram that works in another mboard , or any ram you buy or have lying around, may not work properly, or sometimes, not at all - even if it physically fits and is the right overall type (e.g. SDram, DDR, DDR2, etc.; PCxxxx, xxx mhz) for your mboard. In the worst cases of incompatibilty your mboard WILL NOT BOOT all the way with it installed, and the mboard may not even beep - the ram has to be compatible with the mboard's main chipset, or in the case of recent mboards, compatible with the memory controller built into the cpu.

You should always look up which modules are specified to work for sure BEFORE you buy them, otherwise it's a crap shoot whether modules you try will work properly.

See response 5 in this for some info about ram compatibilty, and some places where you can find out what will work in your mboard for sure:
Correction to that:

Once you know which module ID strings work in your mboard, you can get them from anywhere you like that has ram with those ID strings.

If you have brand name ram, it is usually easy to look up whether it's ID string is in a list of compatible modules found by using your mboard or brand name system model number.
If the ram is generic, that may be difficult or impossible.

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